Preparation of Composite Li4Ti5O12 Electrode for Lithium Rechargeable Batteries by Electrophoretic Deposition

Abstract

Electrodes in commercial lithium rechargeable batteries are comprised of electrode material, electron conductive material, and binder. A painting method has been widely used to prepare the composite electrodes. The electrophoresis deposition (EPD) is expected to simplify a preparation process for the composite electrodes. In this paper, a compatibility of EPD technique with the electrode preparation is studied by using Li4Ti5O12 anode material. A suspension composed of electrode material (Li4Ti5O12), electron conductive material (Ketjen black, KB), binder (polyethylene oxide, PEO), I2, and acetonitrile is supplied for the EPD. A deposit with thickness of approximately 75 μm is successfully obtained at 100 V cm-1 of applied voltage and 2 min of EPD duration. From Raman and TG analysis, the deposit contains Li4Ti5O12, KB, PEO in a weight ratio of 94:2:4, respectively. The charge/discharge test is conducted to evaluate a performance of the deposit as an anode. The charge and discharge curves clearly exhibit a plateau at 1.55 V vs. Li/Li+ which corresponds to the potential of Li ion insertion/deinsertion into/from Li4Ti5O12. This implies the deposit worked as the anode for lithium rechargeable batteries. The discharge capacity of the deposit is 149 mA h g-1, which is 85 % of its theoretical capacity. It is proved that the EPD technique can be applied to the preparation of the composite electrodes.